KEMA, P.O. Box 9035, 6800 ET Arnhem, The Netherlands.
Waste Manag. 2012 Jan;32(1):144-52. doi: 10.1016/j.wasman.2011.08.017. Epub 2011 Oct 2.
In the future, more electricity in the Netherlands will be produced using coal with co-combustion. Due to this, the generated annual ash volume will increase and the chemical composition will be influenced. One of the options for utilization if present markets are saturated and for use of fly ashes with different compositions, is as raw material for lightweight aggregates. This was selected as one of the best utilizations options regarding potential ash volume to be applied, environmental aspects and status of technology. Because of this, a study has been performed to assess the potential utilization of fly ash for the production of lightweight aggregate. Lightweight aggregate has been produced in a laboratory scale rotary kiln. The raw material consisted of class F fly ash with high free lime content. An addition of 8% clay was necessary to get green pellets with sufficient green strength. The basic properties of the produced lightweight aggregate and its behaviour in concrete have been investigated. The concrete has a good compressive strength and its leaching behaviour meets the most stringent requirements of Dutch environmental regulations. The carbon foot print of concrete will be negatively influenced if only the concrete itself is taken into account, but the reduction of the volume weight has advantages regarding design, transport emissions and isolation properties which may counteract this. In the Dutch situation the operational costs are higher than expected potential selling price for the LWA, which implies that the gate fee for the fly ash is negative.
未来，荷兰将更多地使用煤炭混烧来发电。因此，产生的年灰量将会增加，化学成分也将受到影响。如果现有市场饱和，并且要使用成分不同的飞灰，一种利用方式就是将其作为轻骨料的原料。由于潜在的飞灰应用量、环境方面和技术现状，这种方式被选为最佳利用方式之一。因此，开展了一项研究，评估将飞灰用于生产轻骨料的潜力。在实验室规模的回转窑中生产了轻骨料。原料为高游离石灰含量的 F 类飞灰。为了获得具有足够生料强度的绿色球团，需要添加 8%的粘土。研究了所生产的轻骨料的基本性能及其在混凝土中的行为。该混凝土具有良好的抗压强度，其浸出行为符合荷兰环境法规最严格的要求。如果仅考虑混凝土本身，其碳足迹将受到负面影响，但由于设计、运输排放和隔离性能的体积重量减少，可能会抵消这一点。在荷兰的情况下，运营成本高于预期的 LWA 销售价格，这意味着飞灰的入场费为负。
